New in-vitro approaches to the study of carcinogenic and mutagenic agents at the molecular level will be explored. In each of the proposed experiments the synthesis of an appropriate nucleic acid model compound or a specially labeled agent is a requisite step. NMR spectroscopy, especially 13C NMR spectroscopy, will be utilized extensively to investigate the interaction between the agent and the model compound. Three classes of agents will be investigated: (1) alkylating agents, (2) intercalating agents which also bind covalently to the nucleic acid, (3) intercalating agents which do not covalently bind. The objective is to elucidate the molecular mechanisms of action of chemical mutagens and chemical carcinogens.